Should I just keep doing ravenging pit over and over?

Yes drop rates were increased in a hot fix today. Also just salvage your other hearts and craft random hearts. Hot fix provided a substantial buff.

Not sure if this is a farming question, but if not....

You can get wrathful hearts from anywhere.

I only realised last week that a Wrathful affix appears under the elite name if it has a chance to drop a wrathful malignant heart. On top of that, if you have a grey ball you should press it.